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      1 /*	$NetBSD: random.h,v 1.4 2021/12/19 11:49:12 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2018 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef	_LINUX_RANDOM_H_
     33 #define	_LINUX_RANDOM_H_
     34 
     35 #include <sys/cprng.h>
     36 
     37 static inline int
     38 get_random_int(void)
     39 {
     40 	int v;
     41 
     42 	cprng_strong(kern_cprng, &v, sizeof v, 0);
     43 
     44 	return v;
     45 }
     46 
     47 static inline long
     48 get_random_long(void)
     49 {
     50 	long v;
     51 
     52 	cprng_strong(kern_cprng, &v, sizeof v, 0);
     53 
     54 	return v;
     55 }
     56 
     57 static inline uint32_t
     58 get_random_u32(void)
     59 {
     60 	uint32_t v;
     61 
     62 	cprng_strong(kern_cprng, &v, sizeof v, 0);
     63 
     64 	return v;
     65 }
     66 
     67 static inline uint32_t
     68 prandom_u32_max(uint32_t bound)
     69 {
     70 	uint32_t v, min;
     71 
     72 	min = (-bound) % bound;
     73 	do {
     74 		v = get_random_u32();
     75 	} while (v < min);
     76 
     77 	return v % bound;
     78 }
     79 
     80 #endif	/* _LINUX_RANDOM_H_ */
     81